I ran that size on my Autox wheels which are stock terminator wheels (17x9). They fit just right so I feel a 10.5 would stretch the tire and look a little off. Have you checked Toyo's specs to see what width they say the tire will fit?
Im hoping they are just as wide as MT ET street DR. Ive seen people with the MT 275/40 on 17x10.5 and they're not stretch at all. I dont like the stretched look either, I hope someone chimes in with some pictures. I found this on google for the r888 275/40
Proxes R888 features:
-Approved rim width range: 9.0-9.5-11.0 inches
-Weight: 29 lbs
-Tread depth: 0.19 inches
-Tread Width: 10.9 inches
-Inflated dimensions: 25.7 in O.A.D. and 11.0 in O.A.W.
-Static Loaded Radius: 11.9 inches
-Maximum Load: 1653 lbs.
-Maximum Pressure: 51 psi.
-Revs/Mile: 809
Right now my 315 nitto DR sit really close to 12in overall width. I would go with some 17x9s but im already used to the width I currently have. Thanks for your reply !